This invention relates to an independent suspension system, and more particularly an independent suspension system for a mass transit vehicle which provides a significantly lower floor profile.
Mass transit vehicles, such as trolley cars, buses, and the like typically have seats aligned at the lateral sides of the vehicle, with a central aisle and floor extending along the vehicle. In order to facilitate entering and exiting from the vehicle, it is desirable to have the vehicle floor and aisle positioned relatively low to the ground. This provides faster cycle time if the bus stops and more comfort to all passengers, in special children, elderly and passengers with disabilities.
Mass transit vehicles typically have several axles which support, drive and steer the vehicle. Many such vehicles provide a rigid axle having a gear box at a longitudinal end to form an inverted portal axle configuration. Disadvantageously, this arrangement necessarily eliminates the ride benefits of independent suspension systems.
In other known embodiments, independent suspension systems have been available with either a single reduction carrier on relatively lighter vehicles or a double reduction system on relatively heavier vehicles. The reduction carriers are located along the axle centerline in these known independent suspension systems and thus take up a significant amount of packaging space. As these components are aligned along the longitudinal axis of the vehicle, the floor profile must be raised for a significant length of the vehicle. Raising the floor profile in such a manner requires the passengers to climb up to a platform above the axle, which renders that portion of the bus either inaccessible or uncomfortable for people with disabilities.
Accordingly, it is desirable to provide an independent suspension system while maintaining a low floor profile to improve access to the vehicle.